1,593 research outputs found

    Modelling the behaviour of arbitragers and speculators in the crude oil futures market

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    Since the crude oil futures price peaked at $147 per barrel, the role of speculators has come under tremendous scrutiny. The rise in oil price, along with the increased participation of financial traders, led to claims that speculators are responsible for exacerbating crude oil price movements. This study attempts to assess these claims regarding speculative influences on crude oil futures price. Specifically, the study explains the determination of crude oil futures price in terms of arbitrage and speculation. For this purpose a theoretical framework is formulated in which the observed futures price is outlined as a function of the arbitrage price and expected spot price. The arbitrage price, which reflects the influence of arbitrage, is obtained by adjusting the spot price by factors that account for the cost of carry and the convenience yield. The expected spot price, which represents the role of speculation, is estimated by using various expectation formation mechanisms. To determine the relation between the observed futures price, the arbitrage price and the expected spot price of crude oil, cointegration analysis is employed. The empirical results reveal that although both arbitrage and speculation have a significant influence on futures price, arbitrage plays a dominant role in price determination. Moreover, the convenience yield effect is absent from the arbitrage process. The impact of speculation, on the other hand, varies according to the expectation formation mechanism employed and the length of the futures contract. Additionally, speculators form their expectations heterogeneously and switch between different expectation formation mechanisms on the basis of past forecasting performance. The results also show that in the build-up of oil prices after 2003, speculators remained focused on the expected profitability of their trading strategies. Overall, the findings firmly establish that financial traders impact the price dynamics of crude oil future

    Outcome of Lateral Mass Fixation and Fusion – A Comprehensive Analytical Study of 205 Lateral Mass Screws in 35 Patients at Punjab Institute of Neurosciences

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    Objective: To see outcome, accuracy and expected complications in passing lateral mass screws in patients with cervical spine injury, degenerative disease at the cervical spine level and neoplastic lesions.Materials and Methods: In this study, 35 patients were included and 205 screws passed in lateral mass patients’age ranged from 12-70 years (25 males and 10 females) with trauma to the cervical spine, degenerative disease at the cervical spine level and Intradural extramedullary benigntumors and extradural malignant neoplasm.Patients less than 12 years and more than 65 years of age,patients with traumatic ruptured disc causingspinal cord compression anteriorly and operated for cervical spine were excluded from our study.In all patients,we did lateral mass fixation with polyaxial screws and rods under fluoroscopic assistance.For assessment of screws trajectory and position, CT scan cervical spine with 3D reconstruction was performed on a first post op day to confirm screw orientation and direction and for fascet, foraminal, foramen transversarium violations.Results: All screws were passed by using Megrel’s trajectories. Not a single patient had nerve root, cord injury nor vertebral artery injury. One patient had screw pullouts requiring reoperation.12 to 14mm size screws were used under fluoro guidance. On postoperative CT cervical spine with 3D reconstruction shows no breach or violations of any foramen transversarium, nerve root injury or neural foramen penetration by screws. In all patients polyaxial screw/rod construct was used. Conclusion: Cervical spine lateral mass fixation with polyaxial screws is a safe and effective technique in expert hands under fluoroscopic assistance

    Promotion of germination using hydroxamic acid inhibitors of 9-cis-epoxycarotenoid dioxygenase

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    Abscisic acid (ABA) inhibits seed germination and the regulation of ABA biosynthesis has a role in maintenance of seed dormancy. The key rate-limiting step in ABA biosynthesis is catalysed by 9-cis-epoxycarotenoid dioxygenase (NCED). Two hydroxamic acid inhibitors of carotenoid cleavage dioxygenase (CCD), D4 and D7, previously found to inhibit CCD and NCED in vitro, are shown to have the novel property of decreasing mean germination time of tomato (Solanum lycopersicum L.) seeds constitutively overexpressing LeNCED1. Post-germination, D4 exhibited no negative effects on tomato seedling growth in terms of height, dry weight and fresh weight. Tobacco (Nicotiana tabacum L.) seeds containing a tetracycline-inducible LeNCED1 transgene were used to show that germination could be negatively and positively controlled through the chemical induction of gene expression and the chemical inhibition of the NCED protein: application of tetracycline increased mean germination time and delayed hypocotyl emergence in a similar manner to that observed when exogenous ABA was applied and this was reversed by D4 when NCED expression was induced at intermediate levels. D4 also improved germination in lettuce (Lactuca sativa L.) seeds under thermoinhibitory temperatures and in tomato seeds imbibed in high osmolarity solutions of polyethylene glycol. D4 reduced ABA and dihydrophaseic acid accumulation in tomato seeds overexpressing LeNCED1 and reduced ABA accumulation in wild type tomato seeds imbibed on polyethylene glycol. The evidence supports a mode of action of D4 through NCED inhibition, and this molecule provides a lead compound for the design of NCED inhibitors with greater specificity and potency

    Design of Multicationic Copper-Bearing Layered Double Hydroxides for Catalytic Application in Biorefinery

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    Ethanol has been used as a renewable hydrogen-donor in the conversion of a lignin model molecule in subcritical conditions. Noble metal-free porous mixed oxides, obtained by activation of Cu-Ni-Al and Cu-Ni-Fe layered double hydroxide (LDH) precursors, have been used as heterogeneous catalysts for Meerwein-Ponndorf-Verley (MPV) hydrogen transfer and further hydrogenation by ethanol dehydrogenation products. Both the Cu/(Cu+Ni) ratio and the nature of the trivalent cation (Al or Fe) affect the activity of the catalysts, as well as the selectivity towards the different steps of the hydrogenation reactions and the cleavage of lignin-like phenylether bonds. Accounting for the peculiar behaviour of Cu2+ and M(III) cations in the synthesis of LDHs, the coprecipitation of the precursors has been monitored by titration experiments. Structural and textural properties of the catalysts are closely related to the composition of the LDH precursors

    Unravelling the biogeography of secretive taxa by museum collections: the untold story of the black francolin (Francolinus francolinus, Phasianidae) in the Mediterranean

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    The black francolin (Francolinus francolinus) (BF) comprises six morphological subspecies distributed from Cyprus and Turkey across Asia to India. In spite of being renowned as courtly gamebird since the Classic Age, this species suffers from paucity of demographic and molecular studies. In order to update the BF biogeographic pattern by pursuing a thorough sampling across the unsafe and remote areas representing most of the specie’s range, tissues from museum specimens (76, XVIIIth c.-­‐1954) hosted in US and European ornithological collections were genotyped at a 185 bp-­‐long fragment of the mtDNA Control Region gene along with modern birds (205) sequenced at the entire gene. The access to ornithological collections opened the unforeseen opportunity to elucidate the genetic affinity of the extinct populations once residing in the western Mediterranean (Italy, Spain), thus settling the debate about autochthony versus allochthony in that region. Three well-­‐defined haplogroups -­‐ each one including a pair of morphological subspecies and matching the phylogeographical pattern inferred with the whole gene -­‐ were found to reflect a westward adaptive radiation, a more complex scenario being nonetheless disclosed in the Indian sub-­‐continent. The nonnative status of the western Mediterranean BFs was ultimately assessed, a tight genetic affinity with conspecifics from Cyprus and southern Asia being found. This finding, which partly confirmed the invoked importation during the Crusades, pointed to the major human impact on Mediterranean biodiversity through long-­‐distance trade across Asia to satisfy the high demand for exotic species by the European aristocracy during the Medieval times and the Renaissance

    A map of human cancer signaling

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    We conducted a comprehensive analysis of a manually curated human signaling network containing 1634 nodes and 5089 signaling regulatory relations by integrating cancer-associated genetically and epigenetically altered genes. We find that cancer mutated genes are enriched in positive signaling regulatory loops, whereas the cancer-associated methylated genes are enriched in negative signaling regulatory loops. We further characterized an overall picture of the cancer-signaling architectural and functional organization. From the network, we extracted an oncogene-signaling map, which contains 326 nodes, 892 links and the interconnections of mutated and methylated genes. The map can be decomposed into 12 topological regions or oncogene-signaling blocks, including a few ‘oncogene-signaling-dependent blocks' in which frequently used oncogene-signaling events are enriched. One such block, in which the genes are highly mutated and methylated, appears in most tumors and thus plays a central role in cancer signaling. Functional collaborations between two oncogene-signaling-dependent blocks occur in most tumors, although breast and lung tumors exhibit more complex collaborative patterns between multiple blocks than other cancer types. Benchmarking two data sets derived from systematic screening of mutations in tumors further reinforced our findings that, although the mutations are tremendously diverse and complex at the gene level, clear patterns of oncogene-signaling collaborations emerge recurrently at the network level. Finally, the mutated genes in the network could be used to discover novel cancer-associated genes and biomarkers

    Mutations in FRMD7, a newly identified member of the FERM family, cause X-linked idiopathic congenital nystagmus.

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    Idiopathic congenital nystagmus is characterized by involuntary, periodic, predominantly horizontal oscillations of both eyes. We identified 22 mutations in FRMD7 in 26 families with X-linked idiopathic congenital nystagmus. Screening of 42 singleton cases of idiopathic congenital nystagmus (28 male, 14 females) yielded three mutations (7%). We found restricted expression of FRMD7 in human embryonic brain and developing neural retina, suggesting a specific role in the control of eye movement and gaze stability

    Wheat (Triticum aestivum l.) production under drought and heat stress – adverse effects, mechanisms and mitigation: A review

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    Heat and drought stresses are the most important abiotic factors that reduce crops productivity by affecting various physiological and biochemical processes. Thus, selecting cultivars with better drought or heat stress tolerance or breeding for stress tolerance will be helpful in enhancing crop productivity under harsh environments. This review elaborates the physiological basis of high temperature and drought stress tolerance in wheat which can be used as selection criteria in wheat breeding program. In addition, some agronomic selection criteria which are valid and useful in selecting stress tolerant wheat species and cultivars. The review also discussed the valid usage of stress tolerance indices (such as mean productivity (MP), geometric mean productivity (GMP), yield index (YI), yield stability index (YSI), relative productivity (RP%), stress susceptibility index (SSI), and the tolerance index (TOL)) to scan the genotypes against drought and heat stress. Beside these, exogenous application of stress signaling compounds, osmolytes, or certain inorganic salts play a vital role for alleviating adverse effects of abiotic stresses for sustainable wheat production. In addition, applications for soil amendments will also helpful in increasing wheat crop productivity under stressful conditions. All these strategies may be helpful to meet the food demands of the increasing population.Fil: El Sabagh, A.. University of Kafrelsheikh; EgiptoFil: Hossain, A.. Bangladesh Agricultural Research Institute; BangladeshFil: Barutçular, C.. University of Çukurova; TurquĂ­aFil: Islam, Mohammad Sirajul. Hajee Mohammad Danesh Science and Technology University; BangladeshFil: Awan, S. I.. University of the Poonch; PakistĂĄnFil: Galal, A.. University of Kafrelsheikh; EgiptoFil: Iqbal, M. A.. University of the Poonch; PakistĂĄnFil: Sytar, O.. Slovak University of Agriculture; EslovaquiaFil: Yildirim, M.. Dicle University; TurquĂ­aFil: Meena, R. S.. Inistitute of Agricultural Sciences; IndiaFil: Fahad, S.. The University of Swabi; PakistĂĄnFil: Najeeb, U.. The University of Queensland; AustraliaFil: Konuskan, O.. Mustafa Kemal University; TurquĂ­aFil: Habib, R. A.. Bahauddin Zakariya University; PakistĂĄnFil: Llanes, Analia Susana. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas FisicoquĂ­micas y Naturales. Instituto de Investigaciones AgrobiotecnolĂłgicas - Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - CĂłrdoba. Instituto de Investigaciones AgrobiotecnolĂłgicas; Argentina. Universidad Nacional de RĂ­o Cuarto. Facultad de Ciencias Exactas, FisicoquĂ­micas y Naturales. Departamento de Ciencias Naturales; ArgentinaFil: Hussain, S.. University of Agriculture; PakistĂĄnFil: Farooq, M.. Sultan Qaboos University; OmĂĄnFil: Hasanuzzaman, M.. Sher-e-Bangla Agricultural University; BangladeshFil: Abdelaal, K. H.. Kafrelsheikh University; EgiptoFil: Hafez, Y.. Kafrelsheikh University; EgiptoFil: Cig, F.. Siirt University; TurquĂ­aFil: Saneoka, H.. Hiroshima University; JapĂł
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